In recent years, in an image forming apparatus (e.g., a MFP), a sheet finishing apparatus is provided adjacent to a post stage of the MFP in order to apply finishing to sheets after image formation. The sheet finishing apparatus is called finisher. The sheet finishing apparatus staples sheets fed from the MFP or opens punch holes in the sheets and discharges the sheets from a discharge port to a storage tray.
In the past, a user operates an operation unit provided in the image forming apparatus to instruct the sheet finishing apparatus to perform stapling or punching of punch holes. However, if the user fails to perform the operation, sheets are discharged without being subjected to finishing. Therefore, in applying the stapling or the punching of punch holes to the sheets after the sheets are discharged, necessary to convey the sheets to the finisher again with an inserter. Alternatively, the user needs to insert the sheets from the discharge port and staple the sheets.
JP-A-06-340366 discloses an image forming apparatus incorporating a stapler. In the image forming apparatus disclosed in JP-A-06-340366, an auxiliary stapler is provided besides the incorporated stapler. The auxiliary stapler can be removed to the outside of the image forming apparatus. Sheets exceeding a stapling capacity of the incorporated stable are stapled by the auxiliary stapler. However, JP-A-06-340366 is necessary to separately provide the incorporated stapler and the auxiliary stapler.
JP-A-2004-250114 discloses a paper feeding apparatus including a punch unit detachably attachable to an image forming apparatus. When a jam occurs in the paper feeding apparatus disclosed in JP-A-2004-250114, the punch unit is drawn out for maintenance. However, when the punch unit is drawn out, punch holes cannot be opened.